Circuit-controlling means



- R. E. HALL CIRCUIT CONTROLLING MEANS Original Filed Aug. 13, 1919 M WE 0H0 a. mg

h H II 6 INVENTOR g H HIS ATTORNEY i atcnted Get. 9, i923.

BAY ED'XV IN HALL, OF

.onrcneo, rnnrnors, ASSIGNOR ro HALL nnsnanon oon'roimteases TION, A coar'onnrion or DELAWARE. I v I ornonrr-ooizrrnonmne inniins.

Application filed August 13, 1919, Serial To all whom it may concern:

Be it known that l, RAYE. HALL, a citizen ot the United States. and resident of Chicago, in the county of: Cook and State of Illinois, have invented certain new and useful Improvements in Circuit-Controlling Means, of which the following is a specification.

My present invention relates more particularly to circuit changing devices especially adapted for usein place of a key or switch for transmitting wireless telegraph messages, but it will be obvious that itis capable of use in apparatus other than wire less and for purposes other than signalling. it comprises a resistance wire or filament,

' preferably platinum wire adapted to .be

heated, preferably to a high temperature, by flow ot electric current thcrethrough, in combination with a cooling medium, preferably an air jet and means for operatively applying the cooling medium to cool the wire and lower its resistance, to produce the desired changes of current flow in the circuit controlled thereby. The invention may be more ully understood from the following description in connection with the accompanying drawings, in

which i Figure 1 is a diagram showing one form of my invention applied to a wireless telegra h sending system;

igure 2 is a plan view of tape which s shown in edge view in Figure l; and

Figure 3 is a detail viewot a modified arrangement in which the jet is c'ontrollei'l y hand operated means instead of by tape.

In Figure 1 the usual elements or a wire-- less transmitting system operating by the spark discharge method are diagrammatically indicated as an alternating current generator 1, supplying currents to thetransi'ormer primary 2 which inductively 'energizes the secondary 3 whichcharges the condenser 4c discharging through spark 5 and creating oscillatory currents energizing the primary 6, which inductively energizes the secondary Tin the radiating conductor 8. i

As diagrammatically indicated in the drawings, the device comprises afilament 11, preferably of platinum wire and preierably arranged in an open 0011 so that a cons derable length or" it may be located in a small No. 317,118. Renewed re mar fm, 192 s. 1

space. The coil is serially connected in circu t with a source ofelectrical current which it is desired to control. 7 The length and ,di-

ameter of the coil is predetermined with reference to the maximum current flow in this circuit so that the current will normally tend to maintain the coil athi'gh temperature. The filament is preferably of such small cross-section and such considerable lengthas trolled by controlling the application of the;

air jet to the hot'wire-in any .desire'dway. Preferably the jet is fixed in position to discharge upon the coil and a movable member is arranged to be interposed to cut off the jet at desired intervals. For

this. purpose a hand operated key or lever 14 is shown in Figure 8 and a pattern .tape 15 forth'esame purpose is shown in Figures 1 and 2.

' The tape 15 may have longperforations 'Wllllfl the requiredintervals necessary for telegraphic transmission.

a The pattern tape may be out by special machinery operating on typewriter or other principles, so that it represents the message to be sent. 7

as necessary may be simultaneously employed in making thepattern tapes. I Reels of such tapeflmay' be drawn lengthwise be- 16, 16 and short"perforations 17,17 cut ion Obviously, as many transcribers tween the jet and the hot wireat any de sisothelreyerse of the ordinary pre raeaeoe sired speed by a simple mechanism diaby notes in the telephone and the times in grammatically represented by the reed casing 19 having an inlet 20 and an outlet 2 l' i or' thecooliiig 'medium. Such casing serves to render the temperature chaiiges o t' the Wire independent; of local teinperatu're conditions. r p J I ,In lfigure 1 the specific form fand arrangement of the circuit to be controlled by the wire ll i indicated as a shunt across the, circuit from the alternating current gen- In tor 1, to the transformer primary 2. The de cc to be controlled by the resistance c hai ge in the wire fllpis another primary winding 9, wound or connected, in opposi- 'tionto ,the primary 2 and adjusted so that when the wire 11 is c ooledby the blast, the inductive effect on the secondary 3 of the currentsffl win'g in primary 9 will bees actly eq al and po e 0 th y ct' f plii e y 2. Hence there will be no current in sec- 3' fand thefradiating systein ill not be energized so long as the conditionfcontinues. Whenever the cooling i'nediuni' is out off, the wirefll quickly heats up and he re y in ea ed e le'eri 'irre'e y decrease the neutralizing "currents flowing in primary 9,a'nd pr1ma ry 2 .be1ng nolo n utr l th een rr 3, i lp I gized, thus causing the condenser 'and'spark t f unction and the signal waves to be ra-' adiatedfro m the aerial.

,the particular form o f tape shown ,I in Fi ure 2, the receiyed ,signa ls; representing the message will beof .a negative character, that is to sayrthetimes between dots and, dashes/will be the t mes Whenenergy s being, radiated and received, the dots or dashes Will berepresented by times ,WhQil I'IO nergy is being radiated: ,or received. 7 This negative method of functioning isnot important in its efl'ect where the messages are recordedcon tape at the IQCGlVlDg stat on but ,where a t elephone receiver orpther'audibl e indicator is employed, the result will be rto'have the dots and dashes represented by ,breaks or silences n an otherwise cont1nnous; note injthe, ,receiying telephone. I This a a tiee irhi is to have the dots and dashes represented between by silence. If the latter method is as to completely neutralize the remnant of the current still flowing in primary 2. It is noted, however, that the range of resistance change in wire 11 may be Very great and the amount of current thereby diverted from the generator circuit may give enough decrease of current in the work circuit without the use of the bucking coil 9. in certain cases also it is possible to p'ut the hot Wire directly in series with the sour and thereby cause variations su'llicient .tor "the purpose in View. 1 These expe di en ts are pa'rticularly applicable in direct current circuits or where batteries are used .for the source ofcurrent V My temperature operated circuit coirtroller may be also employed in many other known systems, asior instance, in wireless telegraph systems which operate by sending out a continuous radiation and'the signalling is efiected by changing one or more of the tuning ele ments of thesystern. The wire 11 may be bridged around part or all of a tuningelement or part or all o f one of the windings of the high frequency transformer. I Y W b As platinum wire may be hadiriahydesired. lengths and it is in diameters as "small 7 as .0001 inch, there is awide range of "s'e'-.

ilectionrto meet the particular purpose in view and for many purposes it may be found s desirable to use a large number of short lengths of very fine ,wire in parallel with each other instead of a much longer wire of larger diameter. The finer the wire the quicker it will heat and cool and thelonger oxidizing fliiifd may be} employed as the cooling medium." The latter teature 'may bea disadvantage, but in certain cases, it may e m jt a c mp t d fer; by working the iron filament at the critical high temperature range where small changes in temperature cause very great changes in resistance.

The air or other fluid used to cool the wire may be refrigerated below the norm-a1 temperature of the surroundings, as for instance, gas or air stored at high pressure and refrigerated by expansion before conducting it to the jet. In most cases, however, this is unnecessary because in this way the temperature difference can seldom be increased more than 100 degrees or so and equivalent result can usually be attained more conveniently by working the hot wire a hundred degrees or so nearer its melting point.

I claim:

1. In a wireless signalling apparatus, a transmitting system, including a high frequency oscillatory circuit in combination with means for supplying alternating current to said circuit, a transformer between said circuits, a circuit in shunt across the transformer, a circuit including a heat-sens-itive resistance adapted to be heated to high to countervail the current flowing in the primary winding of said transformer.

In the apparatus specified by claim 2, the further feature of having the resistance of the shunt circuit of predetermined value so that when the resistance is ,cooled and passing maximum current, the amount of said current flowing 'in said shunt circuit and through the third winding of the transformer will be sufficient to practically neutralize the current flowing in the primary of said transformer.

4. A circuit controlling resistance, comprising a solid heat sensitive conductor, means for heating it to high temperature by electric currents flowing therein, means for applying a cooling jet to said conductor to lower its resistance and means including a movable member for controlling the time and duration of such application.

5. A circuit controlling resistance, comprising a solid heat sensitive conductor, means for heating it to high temperature by electric currents flowing therein, means for applying a cooling jet to the said conductor to lower its resistance and means including a movable pattern for controlling the time and duration of such application.

6. A circuit controlling resistance, comprising a solid heat sensitive conductor, means for heating it to high temperature by electric currents flowing therein, means for applying a cooling jet to thesaid conductor to lower its resistance and means for controlling said jet, said means including a per-- forated tape and means for feeding the same between the jet and the heat sensitive conductor to alternately interrupt and permit discharge of the jet on the conductor Signed at Montreal, in'the Province of" Quebec and Dominion of Canada this 8 day of August, A. D. 1919.

' RAY EDWIN HALL. 

